Alzheimer disease (AD) remains a clinico-pathologic entity. A definitive diagnosis of AD requires the microscopic identification and neurofibrillary tangles (NFT) and senile plaques (SP) in appropriate density in hippocampus and neocortex in a patient who was clinically demented. In addition, no completely suitable animal model of AD exists yet, so researchers must utilize human tissue to characterize the alterations in the brain associated with AD. The major responsibilities of the Neuropathology Core will be to perform the neuropathological studies necessary to document the diagnosis of AD or other pathological entities in all human brain specimens used in research studies, and to provide clinico-pathologic correlation for ADC Clinical Core patients. Therefore, we will maintain a human brain bank wherein we propose 1) to collect, prepare, evaluate, catalog, store, and distribute well- characterized postmortem brain tissue and other samples from decreased demented and control patients for use in research; 2) to report qualitative and quantitative diagnostic information to physicians, families, and researchers; 3) to work with the Clinical Core to acquire relevant medical records regarding patients' illnesses, including detailed perimortem information (circumstances surrounding death); and 4) to regularly update the central ADC database with diagnostic and other related information on autopsied and biopsied patients.